Need help identifying this pocket watch

by Andrew
(Philadelphia)

Unknown pocket watch dial

Unknown pocket watch case

This pocket watch belonged to my great-grandfather, he received it as a First Communion gift back in the 1880s I'm told. I would like to learn a bit more about it knowing that it belonged to him. There are no identifiers from what I can tell, just the crucifix on the dial and an engraved "M" on the back, which is the 1st letter of our last name. The 30-second marker on the second timer is also upside down. It still keeps good time as I wind it daily.